/Engine/Source/Runtime/Experimental/Chaos/Public/Chaos/Framework/PhysicsProxyBase.h
Returns the Alpha of how much to take previous velocity into account, used to lerp from linear extrapolation to the predicted position based on previous velocity.
[Chaos::FRealSingle](API\Runtime\ChaosCore\Chaos\FRealSingle) GetErrorVelocitySmoothingAlpha ( const int32 ErrorVelocitySmoothDuration )